Exhalation valve filter



FIG. 1 is a perspective view, showing the new design for an exhalation valve filter; the filter is in the form of a nonwoven fibrous web and covers the exhalation valve on a respiratory mask;

FIG. 2 is a rear view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a right side view thereof, the left side view being a mirror image of the right side view.

The broken line showing forms no part of the claimed design, and the shading is provided to illustrate contour only and is not an indication of texture, gloss, etc. 

The ornamental design for an exhalation valve filter, as shown and described. 